At more than $400 million, the cost of building a light rail line between Brush Creek Road and Aspen is nearly triple the price tag of improving bus rapid transit for the Entrance to Aspen, a consultant told area elected officials Thursday.

"Would you like me to give you a moment?" Ralph Trapani, a former Colorado Department of Transportation official and current consultant with the Parsons engineering design firm, asked members of the Elected Officials Transportation Committee after presenting the numbers.

The base cost of a light rail line running the roughly 6 miles from the Brush Creek Intercept Lot to downtown Aspen is $428 million, Trapani said.

That cost estimate would include diesel/electric trains, an at-grade crossing at Brush Creek Road, an at-grade passage through Shale Bluffs, a moving walkway connecting a Highway 82 train stop to the Aspen airport, an underground passage through the roundabout, seven train stops and a final end station at Rubey Park, Trapani said.

If officials want to add options to that plan — including electric-only trains, a viaduct through Shale Bluffs, an underground train stop at the airport and a final stop at Galena and Main streets — the cost of a light rail line increases to $527.8 million, he said.

In addition, operations and maintenance of a light rail line would cost $6 million a year, Trapani said.

By contrast, the base price of improving bus rapid transit is $159.1 million, he said. That would include using natural gas buses and terminating the line at Rubey Park, Trapani said.

If officials wanted to use electric buses only and terminate the main bus line at a new station located at Galena and Main streets, the bus rapid transit cost rises to $200.5 million, Trapani said.

Operating and maintaining such a bus rapid transit system would run $3.2 million a year, he said.

"The biggest distinction is the cost," said Aspen City Councilor Ann Mullins, noting that ridership and service frequency would be about the same for light rail or buses.

Plans for all four options include by-passing the S-curves and routing traffic across the Marolt Open Space — known as the "preferred alternative" — through a "cut and cover" tunnel and over a newly-constructed Castle Creek Bridge to the intersection of Seventh and Main streets. Building just that route across Marolt would cost about $100 million, which is $40 million more than it was estimated to cost in 2008, Trapani said. Car traffic also would follow the preferred alternative across Marolt.

"Parsons worked hard on these cost estimates and we're very comfortable with them," Trapani said.

The ability to phase in a bus rapid transit program "makes it recommendable" over light rail because officials would not have to come up with a huge chunk of money to begin the project, he said. The phasing option is not available with light rail, Trapani said.

Building a rail line through Marolt would not require a vote because area residents already approved such a plan, Pitkin County Commissioner Rachel Richards has said. However, if elected officials decide to go with buses for the Entrance to Aspen, voters would have to approve that plan, which would include two dedicated bus lanes and two normal traffic lanes, officials said Thursday.

That point prompted a discussion among committee members — including the Aspen City Council, the Pitkin County board of commissioners and the Snowmass Village Town Council — about "political will."

Aspen City Councilor Adam Frisch said he wants to know if the community even wants light rail. Frisch also questioned whether it was prudent to spend $100 million to route traffic across Marolt when the consultants said it would only save commuters two or three minutes over the S-curves.

Pitkin County Commissioner Rachel Richards said she could support either buses or light rail. However, officials need to keep an eye on the future and what sort of transportation platform will be optimal in 20 years, she said.

Regardless, both Richards and Commissioner George Newman said elected officials need to figure out the best option and push it forward within the community.

Currently, the Roaring Fork Transportation Authority runs about 458 buses through Rubey Park each day, with buses leaving and arriving about every two or three minutes, said Phil Hoffman, another Parsons consultant.

Implementing an improved bus rapid transit system would cut the frequency of buses to every 10 minutes and cut bus trips through Rubey Park to 224 a day, Hoffman said. A light rail line would further reduce frequency to every 15 minutes and cut the number of Rubey Park bus trips to 144 per day, he said.

System-wide RFTA ridership is expected to increase from 17,600 passengers per day now to 21,200 passengers a day in 2036, which means one million more passengers would be using the system, Hoffman said.

Trapani and his team plan to hold an open house for the public on the options, which will likely take place in May, he said. The committee will meet again in June to talk about the Entrance to Aspen.

The Entrance to Aspen is a decades-long simmering debate about how to alleviate bottleneck traffic jams along the S-curves on Aspen's westside as Highway 82 winds its way into town. The issue has been the subject of 27 votes in the city and county during the past 40 years.

jauslander@aspentimes.com